The kinetic behavior, structure and mechanism of action or rabbit liver aryl sulfatase A will be studied in an effort to understand the molecular basis of its anomalous kinetic behavior - the progressive and rapid inactivation of the enzyme which occurs as it hydrolyzes substrate, and the chemical and/or physical changes which occur when the substrate-inactivated (modified) enzyme is reactivated by the addition of certain ions. The nature of the turnover- or substrate-modified enzyme will be examined for structural changes and for the presence of bound substrate or inhibitor molecules. The subunit structure of the enzyme and its reversible association-dissociation interactions will be studied under varied conditions and associated rates and equilibria enzyme to its anomalous kinetic behavior will be studied. Stopped-flow burst-titration experiments and studies of the pre-steady-state kinetics of hydrolysis of fluorescent substrates will be attempted. Immunological comparisons of rabbit aryl sulfatase A with other possibly related enzymes will be attempted, and immunological comparisons of native and turnover-modified enzymes will be carried out.